Plastic foam spray gun with substantially instantaneous cleaning feature

ABSTRACT

A plastic foam forming and spraying system which utilizes a spray gun that mixes resins and a catalyst in a mixing chamber substantially at the discharge end thereof. Provision is made for instantly cleaning the gun of the catalyst and resin mixture by passing a solvent therethrough to clean the mixture from the interior passages of the gun, and clean the outlet passages thereof by directing air and a solvent, under pressure, therethrough. A special valving arrangement enables the valves to direct a solvent into the passages without permitting the fluid to come into contact with the threads.

United States Patent Higgins PLASTIC FOAM SPRAY GUN WITH SUBSTANTIALLYINSTANTANEOUS CLEANING FEATURE [72] Inventor: James H. Higgins, 703Meadow Dr.,

Burkbumett, Tex. 76354 [22] Filed: July 29, 1971 [21] Appl. No.: 167,256

[52] US. Cl. ..239/112, 239/416.1, 239/422 [51] Int. Cl. ..B05b 15/02[58] Field of Search ..239/399, 400, 401, 403, 405, 239/407, 408, 413,416.1, 416.5, 417.3,

[56] References Cited UNITED STATES PATENTS 476,177 5/ 1892 Thompson..239/414 629,338 7/ 1899 Chelimsky ..239/428 X 1,044,104 1 1/1912Tainter et a1. ..239/400 1,315,765 9/1919 Eckart ..239/417.3 X 1,434,23810/1922 Weber ..239/414 1,667,365 4/ 1928 Ward ..239/414 2,351,3726/1944 Snyder ..239/414 X 2,362,213 11/1944 Miller et a1. ..239/400 X2,984,421 5/1961 Hession ..239/403 X 3,249,304 5/1966 Faro et al..239/112 X [151 3,690,557 [451 Sept. 12,1972

FOREIGN PATENTS OR APPLICATIONS 229,256 7/1960 Australia ..239/414125,174 6/1931 Austria ..239/414 259,728 5/1967 Austria ..239/5 8390,638 8/1957 Denmark ..239/414 593,246 1l/1932 Germany ..239/417.3566,543 1/1945 Great Britain.... ..239/414 Primary Examiner--M. HensonWood, Jr. Assistant ExaminerEdwin D. Grant Attorney-Wayland D. Keith 57ABSTRACT A plastic foam forming and spraying system which utilizes aspray gun that mixes resins and a catalyst in a mixing chambersubstantially at the discharge end thereof. Provision is made forinstantly cleaning the gun of the catalyst and resin mixture by passinga solvent therethrough to clean the mixture from the interior passagesof the gun, and cleanthe outlet passages thereof by directing air and asolvent, under pressure, therethrough. A special valving arrangementenables the valves to direct a solvent into the passages withoutpermitting the fluid to come into contact with the threads.

9 Claims, 7 Drawing Figures Y 1 PLASTIC FOAM SPRAY GUN WITHSUBSTANTIALLY INSTANTANEOUS CLEANING FEATURE BACKGROUND OF THE INVENTIONVarious spray guns have been proposed heretofore for mixing andexpanding resins into foam, by action of a catalyst and air. These, forthe most part, required especially high pressures on the resin andcatalyst, often pressures as much as 600 to 800 lbs. were necessary toproduce expanded foam of the desired quality. This necessitatedexceedingly high pressure pumps, special hose, special fittings andguns, which rendered the system quite dangerous to work around. Theguns, for the most part, required dismantling after each application offoam, in order that the gun be cleaned of all material to prevent thematerial from .hardening. Therefore, the time for operation comparedwith the time for cleaning the machinery made short runs of the foamunprofitable. 1 I

SUMMARY OF THE INVENTION The present invention is so constructed that itcan be used at a relative low pressure for converting resinous materialand a catalyst into an expanded foam and still obtain satisfactoryresults The present invention also enables the cleaning of the guninstantaneously without dismantling, thereby requiring less get readytime and quicker cleaning time.

OBJECTS OF THE INVENTION An object of the invention is to provide aspraying device for mixing internally, within a mixing chamber adjacentthe discharge nozzle in the spraying device, a plurality of materialssupplied from separate sources of supply and fordischarging thesethrough a common nozzle in the form of expanded foam.

Another object of the invention is to provide a spraying system whichincludes a'spray ,gun for receiving, from independent sources, a resin,an accelerator and air to form a foaming mass in a mixing chamberadjacent the discharge nozzle of the system to be discharged from thenozzle thereof.

A further object of the invention is to provide a cleaning system forcleaning the resins and catalysts, before and after they have becomemixed and after they have become mixed, from the spraying device withouthaving to dismantle the spray gun.

Still a further object of the invention is to provide a foam sprayingdevice that is light in weight, easy to assemble and disassemble, low inthe cost of manufacture and which will operate over a long period oftime with a minimum of maintenance.

BRIEF DESCRIPTION OF THE DRAWINGS With these objects in mind and otherswhich will become manifest as the description proceeds, reference is tobe had to the accompanying drawings, in which like reference charactersdesignate like parts in the several views thereof, in which:

FIG. 1 is a side elevational view of the spray gun for converting aresin, a catalyst and air into an expanded plastic foam;

FIG. 2 is a sectional view taken on the line 22 of FIG. 1, looking inthe direction indicated by the arrows;

FIG. 3 is a fragmentary sectional view, taken on the line 3-3 of FIG. 2,looking in the direction indicated by the arrows;

FIG. 4 is a sectional view taken on the line 4-4 of FIG. 1, looking inthe direction indicated by the arrows;

FIG. 5 is a side elevational view of the regulating valve, showing anair hose attached to the tube, with a portion of the tube being-brokenaway and shortened;

FIG. 6 is a side elevational view of a spiral unit to form a mixingchamber for mixing the expanded, foamed resin and catalyst; and

FIG. 7 is a top plan view of thespray gun for mixing and expanding theresins by catalytic action, showing the hose leading therefrom.

DESCRIPTION OF THE PREFERRED EMBODIMENT With more detailed reference tothe drawings, the numeral 1 designates generally a spray gun used formixing resins with a catalyst component and air to produce a foamingaction to expand the plastic resin into a foam, as the foam flows fromthe spray gun.

Various foam spray guns have been proposed heretofore, but these, forthe most part, were hard to clean, when the spraying of foam ceased.However, the present spray gun and system utilizes resin and catalystconduits A and B, which may be in flexible hose, which hose A and B areconnected to the spray gun I, as will best be seen in FIGS. 2 and 7.

' It is preferable to have constant pump pressure both on the plasticand on the catalyst, which resin and catalyst are known to the trade ascompound A and compound B. Therefore, equal pressure is maintained onconduit A and conduit B, so as to direct plastic resin and catalystcomponents into the gun'l through fittings 2 and 3 formed in the body 4,which fittings 2 and 3 pass fluid into openings'6 and 8 in gun l. Thepassages 6 and 8 are sufficiently large for the stems of the Yrespective valves 10 and 12 to pass therethrough and seat on therespective seats 14 and 16, which seats are made from a plastic, such asteflon or other plastic which does not react to the'resin or to thecatalyst being pumped through passages 6 and 8. The passages 6 and 8 areeach reduced in size, within body 4, as indicated at 18 and 20, so therespective valve seats 22 and 24 fit within the outer portions 26 and 28of the respective openings 6 and 8, which form passages, which willpermit the seats 22 and 24 to pass therethrough and shoulder at theinner end of the respective passages 26 and 28. The respective valvemembers 30 and 32, which may be balls which form check valves, whichballs are seated on the respective seats 22 and 24. The balls are heldin the desired seated relation by the respective springs 34 and 36. Thesprings are held in place by the respective cap screws 38 and 40, whichcap screws perform the functions of holding the removable spray head,designated generally by the numeral 42, in place, and of holding thesprings 34 and 36 against the respective ball valves 30 and 32. Capscrews 38 and 40 also serve to plug the portions 26 and 28 of thepassages 6 and 8, so as to maintain these in fluid tight relation.

The body 4 has holes 44 and 46 cross drilled thereinto, which holesintersect within the body 4, and connect with the respective passages 26and 28. The

respective holes 44 and 46 converge into a common passage 48 in sprayhead 42. An O-ring seal surrounds openings 44, 46 and 48 to form a sealor gasket between the spray head 42 and the body 4. The passage 48interconnects with a passage 50 which is within plastic liner 52 of thespray head 42. A spiral member 54 is fitted within cylindrical plasticliner 52, so, as the fluid flows from passage 50 into an annular chamber56, the resin and the catalyst pass around the spiral mixing chamber 55,as best seen in FIG. 6, and is discharged into a second annular chamber58, at the opposite end of the spiral member 54. whereupon, the resinand catalyst flow through a passage 60 in the spiral member 54, into achamber 62 which surrounds the end of a sliding valve member 64, whichvalve member 64 has a tapered valve face 66 to complementally seatwithin bevel seat 68 in plastic valve seat member 70 which is fittedwithin screw cap 72 on spray head 42. The sliding valve member 64 has aplurality of annular sealing ridges formed therearound, which ridgeshave rounded tops to perform a sealing action with the bore 65A of thespiral member 54. This sliding valve member is made of plastic, such asnylon or teflon or other plastic which is not subject to chemical actionby the resin and catalyst components passing thereby. The plastic valveseat member 70 has an axial opening 74 therein, which opening is inregister with an opening 76within sliding valve member 64.

Whenthe valve face 66 seats on said bevel seat 68, the air within tube78, which tube is connected to hollow valve member 64, passes outthrough passage 74 and through passage 80. in the tip 82 of the spraynozzle. A flexible conduit or hose is attached to the tube 78 in fluidtight relation, yet it will permit sliding action of tube 78 so that thevalve face 66 may be moved relative to seat 68 to permit the entrance ofthe resin and the catalyst components, which have been mixed in themixing chamber 62, and into passage 74, whereupon, the air passingthrough tube 78 is mixed with the catalyst and resin, which causes afoaming action which expands the mixture into foam, such as polyurethaneform or other foams, which are subject to catalytic action with a resin,which foam is discharged out through passage 80 into the desiredcontainer, or onto the desired surface.

The present spray gun, depending on several factors, will operate atvarious pressures and it has been found that it will operate with airpressure as low as 25- pounds, with plastics and catalyst being directedinto the gun at pressures from 60 to 180 pounds. The present gun may bemade to operate on much higher pressures, such as 600 and 800 pounds,but it will perform satisfactorily on lower pressures, thereby obviatingthe danger of bursting the hose and other equipment, which might resultin injury to an operator and in loss of equipment.

The. respective conduits A and B have the respective valves 86 and 88therein to enable the resin and/or catalyst to be closed off from thegun, when desired. These valves may be located near the gun or at thepump, (not shown) as desired. A handle H is secured to the body 4 of thegun I by cap screws 90, to enable the spray gun I to be gripped in thehand. A trigger 92 is pivotally mounted on a screw or. pin 94, forpivotal ac tion of the trigger. The upper end of the trigger is roundedat 96, as indicated in FIGS. 2 and 3, andextends into a recess 98 in thebody 4, so as to furnish a fulcrum for the trigger 92. A clamp 100surrounds tube 78 and is held in binding relation thereto by a clampscrew 102, as will best be seen in FIGS. 3 and 4. By securing the clamp100 at the desired place on tube 78, the trigger 92 will open the valve66 the desired degree to control the flow of foam from the passage 80. Aspring 104 surrounds the air tube 78 and is fitted intermediate theclamp 100 and the handle I-I so as to return the tube 78 and valve face66 of valve.64 into seating relation on seat 68.

The normal air pressure, of about 25 lbs., is maintained on hose 84 by acompressor (not shown). A valve 106 is provided within the conduitsystem intermediate the spray gun 1 and the source of air pressure.

A conduit, such as a flexible hose 108, having a valve 1 10 therein, isconnected .to a fitting 112 on body 4, as will best be seen in FIGS. 1,2 and 4, which fitting 112 connects with a cross drilled passage .114 inbody 4 for introduction of a cleaning solvent into the gun at thecompletion of the spraying. In this manner, the gun can be cleanedsubstantially instantaneously without dismantling, and be ready for asubsequent spraying operation.

The valves 10 and 12 are unique in that each has 0- ring sealingelements 116 intermediate the fluid being controlled by the valve andthe threads 118 of the respective valves 10 and 12, which will preventleakage of fluid into the threads which might harden therein and therebyrender the valve useless. The threads 118 are within the respectivepacking glands 120, which packing glands each have threads 1-22 thereonso that the gland and valve may be removed, repaired and/or replacedwith a minimum of disruption to the system. Furthermore, the valve seats14 and 16 may be easily removed and replaced by removing valves 10 and12. The valves 10 and 12 control the'admission of a cleaning solvent,such as acetone, into the passages 18 and 20, and by utilizing thepressure on the hose 108, the acetone will flow by ball check valves30and 32 and will cleanse the springs 26 and 28, passages 44 and 46, andwill pass into the common passage 48 and into passage 50 on the samecourse as followed by the resins and catalysts, thereby to cleanse theannular and spiral mixing chambers, as well as the passages 60, 74 and80.

The valves 10 and 12 have the respective control knobs 124 and 126thereon for controlling the flow of solvent to the respective passages18 and 20.

OPERATION valve member 64 of spray gun I, will create foam of variousdensities which may be directed into molds or onto a surface as acoating, to foam an insulation or for other purposes. FIG. 7 illustratesa spray gun to which a plurality of hose are attached, four in thepresent instance, two for admitting the respective compounds A and Bthrough the respective hose A and B and for admitting air through hose84. The compound A passes from hose A into passages 6 and 18 and beneathspring pressed ball valve 30 into passage 26 and thence into passage 44.Simultaneously, preferably at the same pressure, compound B passes fromhose B into passages 8 and 20 beneath spring pressed ball valve 32 intopassage 46. Both the compounds A and B, which are primarily resins andcatalysts, are liquid until after they reach the juncture of passages 44and 46. The liquids then .pass through passages 48 and 50 into annularmixing chamber 52, whereupon the pressure on hose A and B, together withthe pressure re created by the catalyst expanding the mixture, thematerial is directed around spiral mixing grooves 55 to thoroughly mixthe components A and B. The mixed components move into annular mixingchamber 58 at the end of the spiral grooves 55 and thence throughpassage 60 into a chamber 62, which chamber surrounds valve face 66 thatis complementally seated on seat 68 in plastic valve seat member 70.Upon movement of trigger 92 rearwardly, which trigger is attached to airtube 78 by clamp 100, the air tube moves the valve face 66 away fromseat 68 which permits the mixture of compounds A and B to flow outwardbetween the bevel faces of valve face 66 and seat 68 and with air beingdischarged outward through tube 78 and passage 76 in the valve 64, theexpanded plastic material is admixed with air, the resulting foam beingdischarged out through passage 74 and discharge opening 80 in nozzle 82.

The trigger 92 is pivotally'mounted by pin 94 on clamp 100, whichtrigger has the upper end thereof rounded, as indicated at 96, to extendinto a recess 98 in body 4 and upon pulling the trigger 92 rearward, theclamp 100 will urge the round portion 96 thereof into engagement with aside of recess 98 to compress spring 104 which will permit the valveface 66 to be moved from the bevel seat 68 to cause the spraying orfoaming action. Upon release of trigger 92, the spring 104 will causethe valve face 66 to seat on the bevel seat 68, as will best be seen inFIG. 3.

A conduit 108 is connected with a source of acetone or other desirablesolvent, under pressure, and directs the solvent through the fitting 112into the body 4 of the spray gun, as will best be seen in FIGS. 1, 2 and4. Valves and 12 seat on the respective seats 14 and 16, to normallyprevent the acetone or other solvents from escaping into passages 6 and8, however, when it is desired to clean the spray gun, either the pumpswhich furnish the pressure to conduits A and B are stopped, or valves 86and 88 are closed, or both operations are performed. This will causecompounds A and B to cease flowing through passages 6 and 8. Then, uponopening valves 10 and 12, the acetone will pass through passages 6 and8, 18 and 20 into passages 26 and 28 and through passages 44 and 46 toflow through openings 48 and 50 into annular chamber 56, thence throughspiral grooved mixing chamber 55 into an annular chamber 58 and outthrough passage 68 into chamber 62. With the valve 64 open, the solventwill be discharged between the bevel face 66 of the valve 64 and thebevel seat 68 and thence out through passages 74 and 80, which willcleanse the gun of compounds A and B from passages 6 and 8 and throughpassage 80 of the nozzle of the spray gun. It requires only a fewseconds to accomplish this operation, which enables the cessation ofwork immediately, without the task of dismantling the entire gun andcleaning the individual parts and reassembling these between eachoperation. While this device has been described somewhat in detail withrespect to foamed resins and a catalyst, it is capable of mixing anytype of materials, where thorough mixing at the nozzle is needed.

The present foam spraying gun will operate on equal pressures of 60 tolbs. on thecompounds A and B,

when making polyurethane foam, with 20 to 25 lbs. air

pressure. While this device has been described somewhat in detailrelative to polyurethane foam, it is to be understood that it is themixing of the components within the discharge nozzle and being able toclean the discharge chamber and passages substantially instantly, with asolvent, regardless of what materials are used so long as the solventadmixes with, the material being used in conduits 6 and 8 and can bedischarged under pressure, which are some of the novel features of thisdevice.

lclaim: l. A spray gun for converting a plurality of fluids into anexpandedfoam, which spray gun comprises:

a. a body,

1. said body having a plurality of passages formed therein,

conduits connected with said respective passages for directing fluids,under pressure, into and through, said body, 3. a spray-head connectedto said body, which spray head has a passage formed therethrough, 4.said passage in said spray head being in fluid communication with saidpassages in said body, 5. said spray head having a' mixing chamberformed therein, 6. said spray head having a discharge opening formedtherein, which opening is in fluid communication with the passage insaid spray head, b. two of said passages in said body converging intosaid mixing chamber in said spray head to direct two fluids thereintofor intimate mixing thereof, I

c. a valve member slidably mounted in said spray head,

1. said valve member having a longitudinal passage formed therethrough,

2. said valve member closing the discharge opening in said spray head,when in one position, to keep said first mentioned fluids from passingtherethrough,

3. said sliding valve member being movable longitudinally to permit saidfirst mentioned fluids to escape from said mixing chamber, and

. a tube connected to said sliding valve member in axial relation, andbeing slidable therewith, for directing a further fluid therethrough andthrough the axial opening of said sliding valve member to simultaneouslymix with said first mentioned fluids to form an expanded foam.

2. A spray gun for converting a plurality of fluids into an expandedfoam, as defined in claim 1; wherein a. said mixing chamber extendsspirally within said spray head, b. a discharge nozzle is mounted onsaid spray head,

and

c. said discharge nozzle has an axial opening formed therein, whichopening is in fluid communication with said chamber in said spray head,when said sliding valve member is open.

3. A spray gun for converting a plurality of fluids into an expandedfoam, as defined in claim 1; wherein a. said valve member is mountedwithin said spray head for longitudinal movement therein,

1. said valve member having an axial opening formed therethrough,

b. said spray head having a valve seat which is in fluid communicationwith the axial opening in said nozzle, and

c. said sliding valve member being adapted to seat in complementaryrelation on said valve seat, when in one position to simultaneouslyclose the passages leading from said body.

4. A spray gun for converting a plurality of fluids into an expandedfoam, as defined in claim 1; wherein a. said spray head has a firstannular chamber formed therein, which is said mixing chamber, whichchamber is in fluid communication with said converging passages in saidbody,

b. said spray head having-a .spiral chamber formed therein, which spiralchamber is in fluid communication with said annular chamber,

c. said spray head having a second annular chamber formed therein, whichsecond annular chamber is in fluid communication with said spiralchamber, and

d. the discharge opening in said spray head being in fluid communicationwith said annular chamber when said sliding valve member is open.

5. A spray gun for converting a plurality of fluids into an expandedfoam, as defined in claim 1; wherein a. a further of said passageswithin said body is interconnected with said first two mentionedpassages,

b. a conduit connected to said further passage in fluid communication,through which conduit a solvent is directed, under pressure, into saidfurther passage, and

c. valve means within said passage to selectively control the flow ofsolvent into and through said first two mentioned passages and throughsaid spray head for cleaning said passages and for cleaning the chambersof said spray head and the discharge opening thereof.

6. A spray gun for converting a plurality of fluids into an expandedfoam, as defined in claim 5; wherein a. said valve means includes twovalves in axial alignment, which pass through the respective first twomentioned passages and seat in said further passage, and I 1. controlmeans on each said valve to open and close said valves.

7. A spray gun for converting a'plurality of fluids into an expandedfoam, as defined in claim 5; wherein a. check valve means is positionedin each said two first mentioned passages to direct the flow of fluid insaid passages in one direction only.

8. A spray gun for converting a plurality of fluids into an expandedfoam, as defined in claim 3; wherein a. a handle is mounted on saidspray gun,

b. a flexible conduit is connected in fluid communisatent saanasfam issate a gin dinally of said body, and

c. a trigger pivotally connected to said tube and to said body and beingmounted a spaced distance forward of said handle for manual operation sosaid trigger will move said tube and said sliding valve memberlongitudinally of said spray head to control the discharge of foam fromthe discharge opening of said spray head while said trigger and saidhandle are manually operated.

9. A spray gun for converting a plurality of fluids into an expandedfoam, as defined in claim 8; wherein a. a spring surrounds said tube andis interposed in abutting relation between said handle and said triggerto move said tube longitudinally to seat said sliding valve member onsaid valve seat in said spray head, when said sliding valve member is inone position.

2. A spray gun for converting a plurality of fluids into an expandedfoam, as defined in claim 1; wherein a. said mixing chamber extendsspirally within said spray head, b. a discharge nozzle is mounted onsaid spray head, and c. said discharge nozzle has an axial openingformed therein, which opening is in fluid communication with saidchamber in said spray head, when said sliding valve member is open. 2.conduits connected with said respective passages for directing fluids,under pressure, into and through, said body,
 2. said valve memberclosing the discharge opening in said spray head, when in one position,to keep said first mentioned fluids from passing therethrough,
 3. aspray head connected to said body, which spray head has a passage formedtherethrough,
 3. said sliding valve member being movable longitudinallyto permit said first mentioned fluids to escape from said mixingchamber, and d. a tube connected to said sliding valve member in axialrelation, and being slidable therewith, for directing a further fluidtherethrough and through the axial opening of said sliding valve memberto simultaneously mix with said first mentioned fluids to form anexpanded foam.
 3. A spray gun for converting a plurality of fluids intoan expanded foam, as defined in claim 1; wherein a. said valve member ismounted within said spray head for longitudinal movement therein,
 4. Aspray gun for converting a plurality of fluids into an expanded foam, asdefined in claim 1; wherein a. said spray head has a first annularchamber formed therein, which is said mixing chamber, which chamber isin fluid communication with said converging passages in said body, b.said spray head having a spiral chamber formed therein, which spiralchamber is in fluid communication with said annular chamber, c. saidspray head having a second annular chamber formed therein, which secondannular chamber is in fluid communication with said spiral chamber, andd. the discharge opening in said spray head being in fluid communicationwith said annular chamber when said sliding valve member is open. 4.said passage in said spray head being in fluid communication with saidpassages in said body,
 5. said spray head having a mixing chamber formedtherein,
 5. A spray gun for converting a plurality of fluids into anexpanded foam, as defined in claim 1; wherein a. a further of saidpassages within said body is interconnected with said first twomentioned passages, b. a conduit connected to said further passage influid communication, through which conduit a solvent is directed, underpressure, into said further passage, and c. valve means within saidpassage to selectively control the flow of solvent into and through saidfirst two mentioned passages and through said spray head for cleaningsaid passages and for cleaning the chambers of said spray head and thedischarge opening thereof.
 6. A spray gun for converting a plurality offluids into an expanded foam, as defined in claim 5; wherein a. saidvalve means includes two valves in axial alignment, which pass throughthe respective first two mentioned passages and seat in said furtherpassage, and
 6. said spray head having a discharge opening formedtherein, which opening is in fluid communication with the passage insaid spray head, b. two of said passages in said body converging intosaid mixing chamber in said spray head to direct two fluids thereintofor intimate mixing thereof, c. a valve member slidably mounted in saidspray head,
 7. A spray gun for converting a plurality of fluids into anexpanded foam, as defined in claim 5; wherein a. check valve means ispositioned in each said two first mentioned passages to direct the flowof fluid in said passages in one direction only.
 8. A spray gun forconverting a plurality of fluids into an expanded foam, as defined inclaim 3; wherein a. a handle is mounted on said spray gun, b. a flexibleconduit is connected in fluid communication with said tube on which saidsliding valve member is mounted, which tube extends longitudinally ofsaid body, and c. a trigger pivotally connected to said tube And to saidbody and being mounted a spaced distance forward of said handle formanual operation so said trigger will move said tube and said slidingvalve member longitudinally of said spray head to control the dischargeof foam from the discharge opening of said spray head while said triggerand said handle are manually operated.
 9. A spray gun for converting aplurality of fluids into an expanded foam, as defined in claim 8;wherein a. a spring surrounds said tube and is interposed in abuttingrelation between said handle and said trigger to move said tubelongitudinally to seat said sliding valve member on said valve seat insaid spray head, when said sliding valve member is in one position.